Tropical Forests

Abstract Tropical forests occupy approximately 10% of the world's total land area, but they play a disproportionate role in global carbon and water cycles, and are believed to house more than half of the world's species. Tropical forests occupy a wide range of environments, and the structure and species composition vary with dry season length, altitude above sea level, and the occurrence of extreme soil types or regular inundation by fresh or saline water. Lowland evergreen rain forests are the most diverse ecosystems on Earth, but the processes that generated and maintain this diversity are not fully understood. Forests are under threat throughout the tropics from clearance for agriculture, logging for timber, hunting, fires, climate change and other human impacts. Major conservation priorities include protecting large areas of intact forest ecosystems where still possible, improving the management of logged forests, controlling hunting, and reconnecting isolated forest fragments by restoring forest between them. Key Concepts: Tropical forests house the majority of the world's species. Tropical forests have a large role in global carbon and water cycles. Distinctive types of tropical forests occur in different climates, on extreme soil types, and in areas subject to flooding by fresh or saline water. Forests in similar environments but different tropical regions also differ, because the forest communities in each region have different evolutionary histories. Lowland rain forests are far more diverse than any other terrestrial ecosystem, at least partly because of the age and continuity of warm, wet tropical climates. The most important commercial product from tropical forests is timber, but these forests also provide many other products and services to local human communities. The biggest threats to tropical forests and their species are conversion to agriculture, hunting and unsustainable logging. Legally protected areas are still the cornerstone of tropical forest conservation, but sustainable exploitation for timber and other products offers an alternative in countries with good governance capabilities.